1. Field of the Invention
The present invention generally relates to data storage and, more specifically, to systems and methods for controlling emitters of data storage devices employing atomic resolution storage (ARS).
2. Background of the Invention
The apparent insatiability of consumers for higher capacity, higher speed memory storage devices has led to the development of memory storage techniques such as atomic resolution storage (ARS). As is known, a storage device employing ARS technology includes a number of electron emitters, such as field emitters, for example, that are adapted to write data to and read data from various storage areas of a storage medium.
During operation, an electron beam current is extracted from an emitter towards a corresponding storage area. Writing of data from an emitter to a storage area is accomplished by temporarily increasing the power density of the electron beam current to modify the structural state of the surface of the storage area. In contrast, reading data from the storage area is accomplished by observing the effect of the storage area on the electron beam of the emitter, or the effect of the electron beam on the storage area. More specifically, reading typically is accomplished by collecting secondary and/or backscattered electrons when an electron beam, i.e., an electron beam with a lower power density than that of the electron beam utilized for writing data to the storage area, is applied to the storage medium.
An ARS storage medium is formed of material characterized by a structural state that can be changed from crystalline to amorphous by a beam of electrons. Since the amorphous state has a different secondary electron emission coefficient (SEEC) and backscattered electron coefficient (BEC) than the crystalline state, a different number of secondary and backscattered electrons are emitted from each storage area, in response to an electron beam, depending upon the current structural state of that storage area. Thus, by measuring the number of secondary and backscattered electrons, the structural state of the storage area and, therefore, the data stored by the storage area, may be determined.
Emitters utilized in ARS generally may be characterized as electrically noisy components. This characterization may be due, at least in part, through the scale of these components and/or the typically low currents that are associated with these components. So configured, these emitters may tend to facilitate extraction of spurious electron being currents when utilizing a level currents source.
Therefore, there is a need for improved devices, systems and methods that address these and/or other shortcomings of the prior art.
Briefly described, the present invention relates to atomic resolution storage (ARS) techniques. In this regard, embodiments of the present invention may be construed as providing memory storage devices that employ, at least in part, ARS technology. A preferred embodiment of the memory storage device includes a storage medium that defines one or more coverage areas. Each of the coverage areas incorporates a storage area that is configurable in one of a plurality of structural states. Typically, the structural states represent information stored in the storage area. Electron beam emitters electrically communicate with the storage medium, with the storage medium and the emitters being configured to move relative to each other. So configured, each emitter is capable of providing a beam of electrons to a respective one of the coverage areas.
The aforementioned embodiment of the memory storage device also includes a first current source that selectively electrically communicates with at least one of the emitters. Additionally, a control system electrically communicates with the first current source. The control system facilitates a controlled current flow from the first current source to the at least one emitter so as to enable the at least one emitter to provide a beam of electrons to a respective one of the coverage areas.
Some embodiments of the present invention may be construed as providing methods for providing current to an emitter of a memory storage device. In a preferred embodiment, the method includes the steps of providing a first current source and a first current mirror electrically communicating with the first current source, and controlling a current flow from the first current source to an emitter. Preferably, controlling the current flow is facilitated by providing current from the first current source to the first current mirror, and selectively providing current from the first current mirror to the emitter.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such features and advantages be included herein within the scope of the present invention, as defined in the appended claims.